1. Field of the Invention
The present invention relates to the field of polarizing plates for a liquid crystal display (LCD) and a liquid crystal display using polarizing plates.
2. Description of the Related Art
Recently, the use of LCDs in personal computers (PCs) or the like has increased sharply, and they have been used for monitors as well.
Typical polarizing plates used for display devices such as LCDs are produced from polyvinyl alcohol (PVA) films or the like. The PVA films are dyed with dichroic iodine or dichroic dyestuff, and then crosslinked with boric acid, borax or the like. The films are then be stretched uniaxially. The stretching step can be included in the dyeing and/or crosslinking steps. Alternatively, the film can be stretched before and/or after the dyeing and/or crosslinking steps. In general, the film is dried in a dryer or the like after the dyeing and crosslinking steps, and it is bonded to a protective layer such as a triacetylcellulose (TAC) film through an adhesive.
A polarizing plate used for a LCD is required to have high transmittance and a high polarization degree. For this purpose, a PVA film should be stretched at a high ratio. However, when a PVA film is stretched at a high stretch ratio, irregularities like grooves on a record may be generated on the polarizer surface, and this will impair the appearance. The irregularities can be recognized even through a protective film like a TAC film or a polyethylene terephthalate (PET) film bonded to the polarizer. As a result, images provided by the polarizing plate will be blurred when reflected light is applied.